A wide variety of coating compositions (such as, for example, paints, paper coatings, and floor polishes) are desirably improved by including a leveling agent in the composition. For example, tributoxyethylphosphate has been used as a leveling agent in floor polish. However, some organophosphate compounds show neurotoxicity, so it is desired to find effective leveling agents other that organophosphates. Some leveling agents that have been described are as follows: Japanese Patent Publication (kokai) No. 206476/84 describes a polyalkoxylate of a linear aliphatic alcohol. Japanese Patent Publication (kokai) No. 80933/94 describes use of adipic acid esters as a leveling agent. Japanese Patent Publication (kokai) No. 315255/99 describes use of a cumarin or derivatives thereof as a leveling agent. In addition, Japanese Patent Publication (kokai) No. 2004-107586 describes improvement of leveling ability by combining a specific structured plasticizing agent and a polyoxyalkylene alkylether type nonionic surfactant.
However, it has been found that the effects of the publicly known leveling agents were not sufficient compared to the effects of tributoxyethylphosphate. It has been further found that the leveling effectiveness of tributoxyethylphosphate can be matched or exceeded by leveling agents that contain monoesters of C7-C10 aliphatic monocarboxylic acids with dihydric alcohols and/or monoesters or diesters of C7-C10 aliphatic monocarboxylic acids with trihydric alcohols.
It is further desired to improve the ease of making a coating composition by providing an effective, non-organophosphate leveling agent and an aqueous polymer dispersion in a single package. However, it has been found that unstable compositions result when some mixtures are made of useful aqueous polymer dispersions plus one or more monoesters of C7-C10 aliphatic monocarboxylic acids with dihydric alcohols and/or one or more monoesters or diesters of C7-C10 aliphatic monocarboxylic acids with trihydric alcohols. Such unstable compositions exhibit gel formation, coagulation, other undesirable effects, or combinations thereof. It is therefore desired to provide stable mixtures of useful aqueous polymer dispersions with such monoesters and/or diesters.